The present invention relates to a fuel-air mixture arrangement with an air-compressing supercharger for a combustion engine with continuous fuel injection into the intake pipe which holds an air quantity meter, consisting of a pivotal ram flap and a throttle flap arranged behind each other. The air meter, depending on its deflection, actuates a fuel metering unit, fuel metering taking place at constant pressure drop in the fuel; this pressure drop is, however, variable depending on certain coefficients. The pressure drop on a second valve is variable by means of a control pressure valve to which the controlling variables are applied. This second valve keeps the set pressure drop at the cross sections of the fuel metering unit constant.
Such an arrangement is known from German Patent No. 23 40 834 and from German Laid-Open Document 25 57 968.
It is known to place such an air measuring device upstream of an air-compressing supercharger, for example, an exhaust gas turbosupercharger. However, this has the disadvantage that the path between ram flap and throttle flap is very long. Since the position of the ram flap simultaneously controls the fuel quantity, during a change of the throttle flap position the dead time of the controlled system is so large that the mixture composition is not correct and thus short-timed operating errors occur.
Accordingly, it is an object of the present invention to provide a fuel-air mixture forming arrangement which in the operation with an air compressing supercharger avoids the dead time of the controlled system.
Another object of the present invention is to provide an arrangement of the foregoing character which is substantially simple in construction and may be economically fabricated.
A further object of the present invention is to provide a fuel-air mixture forming arrangement, as described, which may be readily maintained in service and which has a substantially long operating life.